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RE: Precast concrete beam help needed

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The section you described is referred to as a channel slab.  The likelihood of figuring out who the manufacturer was for a building from the 60’s and therefore finding an applicable load table for the members is not likely.  However, if you already know what the internal reinforcing is (and the approximate age of the building in order to estimate the likely yield strength of the rebar), the concrete compressive and have measured the pieces to be able to calculate the section properties then there is nothing stopping you from calculating both the flexural and shear capacity of the section as a spandrel T beam.  I assume that your reference to the internal reinforcing as rebar means that the sections are not prestressed so your calculations will be all that much easier.



D. Matthew Stuart, P.E., S.E.

Structural Department


200 State Highway Nine

Manalapan, NJ 07726-0900

Phone: (732) 577-9000 (Ext. 1283)

FAX: (732) 431-9428

Cell: (908) 309-8657

Email: mstuart(--nospam--at)





-----Original Message-----
From: Ken Peoples [mailto:kspeoples(--nospam--at)]
Sent: Friday, January 28, 2005 8:04 AM
To: Seaint
Subject: Precast concrete beam help needed


I have been asked to evaluate the floor rating for a manufacturing building that has precast concrete beams.  They are sort of like double tees without the flanges on either side.  An upside-down u-shape.  I'm sure there is a name for these, but I don't know what it is.  Anyway, I had a testing agency do some field testing and they came up with the concrete strength and rebar size and location and I was wondering if any of you might have any kind of load tables for these.  I would be happy to fax or email the section to you if it helps.  Any help is appreciated.


I don't really know, but am guessing that the building was built around 1968 based on some sprinkler drawings that I have.  Of course they have the sprinkler drawings and not the structural drawings.


Thanks for your help.


Best regards,




Kenneth S. Peoples, P. E.
Lehigh Valley Technical Associates, Inc.
1584 Weaversville Road
Northampton, PA 18067


Phone: 610-262-6345
Email: kpeoples(--nospam--at)